Sources of Onboard Fumes and Smoke Reported by U.S. Airlines

Abstract

This paper describes the relative frequency of reports of oil and hydraulic fluid fumes in the ventilation supply air (“fume events”) compared to other types of fumes and smoke reported by U.S. airlines over 10 years. The author reviewed and categorized 12,417 fume/smoke reports submitted to the aviation regulator to comply with the primary maintenance reporting regulation (14 CFR § 121.703) from 2002–2011. The most commonly documented category of onboard fumes/smoke was electrical (37%). Combining the categories of “bleed-sourced”, “oil”, and “hydraulic fluid” created the second most prevalent category (26%). The remaining sources of onboard fumes/smoke are also reported. To put the data in context, the fume event reporting regulations are described, along with examples of ways in which certain events are underreported. These data were reported by U.S. airlines, but aviation regulations are harmonized globally, so the data likely also reflect onboard sources of fumes and smoke reported in other countries with equivalent aviation systems. The data provide insight into the relative frequency of the types of reported fumes and smoke on aircraft, which should drive design, operational, and maintenance actions to mitigate onboard exposure. The data also provide insight into how to improve current fume event reporting rules.

Health consequences of exposure to aircraft contaminated air and fume events: a narrative review and medical protocol for the investigation of exposed aircrew and passengers

“…Other sources of fumes/smoke that can be supplied to the aircraft cabin and flight deck include electrical faults, fan failures, deicing fluid, exhaust, and galley equipment [ 85 , 86 ]. However, oil and hydraulic fluid are the second most commonly reported type of fumes/smoke that are documented by US airlines, with only electrical fumes being more prevalent [ 85 ].…”

“…Low level oil leakage is well recognised [ 1 - 8 , 38 , 85 , 87 - 91 ]. The oil leakage due to engine operating conditions “pollutes the cabin/cockpit air” [ 92 ].…”

“…The average number of acute events reported per day on the US fleet via official US databases is 5.3 events [ 93 ]. However, the lack of training of aircrew regarding fume events has led to significant under-reporting [ 25 , 49 , 84 , 85 ]. Contamination events are widely distributed across almost all common aircraft models.…”

Comment on: Chen R, Fang L, Liu J, Herbig B, Norrefeldt V, Mayer F, Fox R, Wargocki, P. Cabin air quality on non‐smoking commercial flights: A review of published data on airborne pollutants

“…3 This is relevant because most of the contaminants in this review are sourced to complex mixtures, which are consistent with the types of fumes and smoke that US airlines report to the aviation regulator. 4 Finally, the diversity in exposure limits published by different authorities for a single chemical (presented in table 7 of Chen et al) highlights the fallacy that a single number can define the boundary between what is and is not acceptable.…”

Oil Fumes, Flight Safety, and the NTSB

“…In addition to the design regulations, U.S. airlines are required to comply with three FAA reporting regulations for fume events (Table 4), but all are underutilized [22].…”